This experiment uses two glass jars—one covered and one open—to demonstrate how greenhouse gases trap heat in the Earth's atmosphere. By measuring the temperature change in both jars when placed in sunlight, you can see the greenhouse effect in action.
If two jars, one covered and one uncovered, are placed in direct sunlight, then the temperature inside the covered jar will increase more than the temperature in the uncovered jar because the cover will trap heat, simulating the greenhouse effect.
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Place a thermometer inside each jar. If necessary, tape it to the inside so you can read the temperature from the outside.
Cover one of the jars with a lid or a tight layer of plastic wrap. This is your 'greenhouse' jar.
Leave the other jar open. This is your 'control' jar.
Place both jars in a sunny spot, either outdoors or on a sunny windowsill.
Record the starting temperature in both jars.
Record the temperature in both jars every 15 minutes for one hour.
Compare the temperature changes in the two jars.
Create a graph to show how the temperature changed over time for each jar.
The temperature in the covered jar will rise faster and reach a higher temperature than the temperature in the open jar. This is because the sunlight (shortwave radiation) passes through the glass and heats the air inside. The heat (longwave radiation) is then trapped by the glass cover and cannot escape, causing the temperature to build up. This is analogous to how greenhouse gases trap heat in the Earth's atmosphere.
The presence or absence of a cover on the jar.
The temperature inside the jar.
The size of the jars, the type of thermometers, and the amount of sunlight they receive.
Be careful when handling glass jars. The jars can get hot in the sun, so handle them with care.
Use a line graph to clearly show the difference in temperature change between the two jars.
Create a diagram that explains how the greenhouse effect works on Earth, and how your experiment models it.
Discuss the importance of the greenhouse effect for life on Earth, as well as the problems caused by an enhanced greenhouse effect (global warming).
